Pallet rack systems are used extensively in many industries. Foods or other commodities are often palletized. Typically a palletized commodity will be off loaded from a truck, and a motorized pallet handler will move the palletized commodity to a storage area having pallet racks. Pallet racks are used to conserve floor space. It is desirable to stack the pallets on racks to allow the palletized materials to be selectively removed from the storage area.
Typically, the pallet racks have vertically spaced locking apertures in columns. Shelf beams are connected to the columns at the locking apertures by a releasable pallet rack lock. It is necessary to adjust selectively the height of the space between shelf beams of a pallet rack in certain operations. A shelf beam includes a pallet rack lock on each end. Each pallet rack lock includes a pair of load bearing studs. The load bearing studs fit into selected locking apertures in a column. To prevent the shelf beam from becoming detached from the column, the pallet rack lock includes a mechanism for releasably securing the beam to the column which lock requires a positive action to disengage a part from the column before the load bearing studs may be disengaged from their respective locking apertures.
There are a number of rack lock constructions which are well known. A typical rack lock is shown in U.S. Pat. No. 4,955,743 to King entitled "Rack Beam Latch" which was issued Sep. 11, 1990. U.S. Pat. No. 3,612,290 to Evans entitled "Releasable Key Clamp For A Pallet Rack" which issued Oct. 12, 1971, and U.S. Pat. No. 3,273,720 to Seiz for "Storage Racks" which issued on Sep. 20, 1966, also shows rack locks. Each of the three patents mentioned above have a basic construction in common in that a latching or locking member is held in its latch position by a resilient spring member. The resilient spring member is bent to disengage the latching member to release the locking member.
Generally, individuals who work with the pallet racks do not handle the pallet rack locks in a delicate manner. On occasion, a workman will insert a screwdriver under the resilient member to pry the latching member out of contact with a column. This operation sometimes results in the resilient member being bent beyond its elastic limit so that it takes a permanent set with the latching member being decommissioned as shown in FIG. 4 of the accompanying drawings.
Once the latching member is rendered inoperative, there is no safety locking of the end of a shelf beam to the column. The shelf beam can be disconnected from the column during normal operations in the storage area either by removing a pallet or positioning a pallet into a pallet rack.
It is a primary object of the present invention to provide a pallet rack lock which includes built-in self protection for the resilient member so that it will not be readily permanently deformed and thereby rendered inoperative.